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1.
J Environ Sci (China) ; 85: 35-45, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31471029

RESUMO

Imazethapyr (IM) is an acetolactate synthase (ALS)-inhibiting herbicide that has been widely used in recent years. However, IM spraying can lead to the accumulation of herbicide residues in leaves. Here, we determined the effects of IM spraying on the plant growth and leaf surface microbial communities of Arabidopsis thaliana after 7 and 14 days of exposure. The results suggested that IM spraying inhibited plant growth. Fresh weight decreased to 48% and 26% of the control value after 7 and 14 days, respectively, of 0.035 kg/ha IM exposure. In addition, anthocyanin content increased 9.2-fold and 37.2-fold relative to the control content after 7 and 14 days of treatment, respectively. Furthermore, IM spraying destroyed the cell structures of the leaves, as evidenced by increases in the number of starch granules and the stomatal closure rate. Reductions in photosynthetic efficiency and antioxidant enzyme activity were observed after IM spraying, especially after 14 days of exposure. The diversity and evenness of the leaf microbiota were not affected by IM treatment, but the composition of community structure at the genus level was altered by IM spraying. Imazethapyr application increased the abundance of Pseudomonas, a genus that includes species pathogenic to plants and humans, indicating that IM potentially increased the abundance of pathogenic bacteria on leaves. Our findings increase our understanding of the relationships between herbicide application and the microbial community structures on plant leaves, and they provide a new perspective for studying the ecological safety of herbicide usage.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Herbicidas/toxicidade , Microbiota/efeitos dos fármacos , Ácidos Nicotínicos/toxicidade , Folhas de Planta/microbiologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/microbiologia , Folhas de Planta/efeitos dos fármacos
2.
J Agric Food Chem ; 67(37): 10489-10497, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31452371

RESUMO

In order to develop a novel herbicide containing the ß-triketone motif, a series of 4-hydroxyl-3-(2-phenoxyacetyl)-pyran-2-one derivatives were designed and synthesized. The bioassay results showed that compound II15 had good pre-emergent herbicidal activity even at a dosage of 187.5 g ha-1. Moreover, compound II15 showed a broader spectrum of weed control when compared with a commercial herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), and displayed good crop safety to Triticum aestivum L. and Zea mays Linn. when applied at 375 g ha-1 under pre-emergence conditions, which indicated its great potential as a herbicide. More importantly, studying the molecular mode of action of compound II15 revealed that the novel triketone structure is a proherbicide of its corresponding phenoxyacetic acid auxin herbicide, which has a herbicidal mechanism similar to that of 2,4-D. The present work indicates that the 4-hydroxyl-3-(2-phenoxyacetyl)-pyran-2-one motif may be a potential lead structure for further development of novel auxin-type herbicides.


Assuntos
Herbicidas/síntese química , Herbicidas/farmacologia , Plantas Daninhas/efeitos dos fármacos , Arabidopsis/efeitos dos fármacos , Desenho de Drogas , Herbicidas/química , Estrutura Molecular , Plantas Daninhas/crescimento & desenvolvimento , Relação Estrutura-Atividade , Controle de Plantas Daninhas , Zea mays/efeitos dos fármacos
3.
Dokl Biochem Biophys ; 486(1): 163-167, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31367812

RESUMO

The treatment of Arabidopsis thaliana plants with exogenous cytokinin (CK) followed by heat shock (HS) activated the expression of the genes for the plastid transcription machinery but adversely affected the plant viability. Abscisic acid (ABA), conversely, promoted maintaining the resistance to HS and had differentially affected different components of the plastid transcriptional complex. This hormone suppressed the accumulation of transcripts of PEP genes and the genes encoding PAP proteins, which are involved in DNA-RNA metabolism. However, it had no effect or activated the expression of NEP genes and PAP genes, which are involved in the redox regulation, as well as the genes encoding the stress-inducible trans-factor (SIG5) and the plastid transcription Ser/Thr protein kinase (cpCK2). Thus, for the adaptation of plants to elevated temperatures, both increase and decrease in the expression of the genes for the plastid transcriptional machinery with the involvement of various regulatory systems, including phytohormones, are equally significant.


Assuntos
Ácido Abscísico/farmacologia , Arabidopsis/efeitos dos fármacos , Citocininas/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Resposta ao Choque Térmico/genética , Plastídeos/genética , Transcrição Genética/efeitos dos fármacos , Arabidopsis/citologia , Arabidopsis/genética , Arabidopsis/fisiologia , Resposta ao Choque Térmico/efeitos dos fármacos , Plastídeos/efeitos dos fármacos
4.
J Agric Food Chem ; 67(32): 8905-8918, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31380641

RESUMO

NAC TFs play crucial roles in response to abiotic stresses in plants. Here, ZmNAC071 was identified as a nuclear located transcriptional repressor. Overexpression of ZmNAC071 in Arabidopsis enhanced sensitivity of transgenic plants to ABA and osmotic stress. The expression levels of SODs, PODs, P5CSs, and AtMYB61 were inhibited by ZmNAC071, which results in reduced ROS scavenging and proline content, increased ROS level, and water loss. Besides, the expression levels of some ABA or abiotic stress-related genes, like ABIs, RD29A, DREBs, and LEAs were also significantly inhibited by ZmNAC071. Yeast one-hybrid assay demonstrated that ZmNAC071 specifically bound to the cis-acting elements containing CGT[G/A] core sequences in the promoter of stress-related genes, suggesting that ZmNAC071 may participate in the regulation of transcription of these genes through recognizing the core sequences CGT[G/A]. These results will facilitate further studies concerning the cis-elements and downstream genes targeted by ZmNAC071 in maize.


Assuntos
Arabidopsis/efeitos dos fármacos , Arabidopsis/fisiologia , Ácido Ascórbico/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/fisiologia , Fatores de Transcrição/genética , Zea mays/genética , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação para Baixo/efeitos dos fármacos , Pressão Osmótica , Plantas Geneticamente Modificadas/genética , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Fatores de Transcrição/metabolismo
5.
J Agric Food Chem ; 67(25): 6911-6920, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31194542

RESUMO

Improving the root system architecture (RSA) under adverse environmental conditions by using biostimulants is emerging as a new way to boost crop productivity. Recently, we have reported the characterization of novel chitosan-based microparticles (CS-MPs) with promising biological properties as rooting agents in lettuce. In this work, we demonstrated that in contrast to bulk chitosan (CS), which exerts root growth inhibition, CS-MPs promoted root growth and development from 1 to 10 µg mL-1 without cytotoxicity effects at higher doses in Arabidopsis and lettuce seedlings. In addition, we studied the mechanistic mode of action of CS-MPs in the development of early RSA in the Arabidopsis model. CS-MPs unchained accurate and sustained spatio-temporal activation of the nuclear auxin signaling pathway. Our findings validated a promising scenario for the application of CS-MPs in the modulation of RSA to respond to changing soil environments and improve crop performance.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Quitosana/química , Quitosana/farmacologia , Ácidos Indolacéticos/farmacologia , Alface/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Arabidopsis/efeitos dos fármacos , Alface/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
6.
Plant Sci ; 284: 57-66, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31084879

RESUMO

The transmembrane transport of NO3- and Cd2+ into plant cell vacuoles relies on the energy from their tonoplast proton pumps, V-ATPase and V-PPase. If the activity of these pumps is reduced, it results in less NO3- and Cd2+ being transported into the vacuoles, which contributes to better nitrogen use efficiency (NUE) and lower Cd2+ tolerance in plants. The physiological mechanisms that regulate the balance between NUE and Cd2+ tolerance remain unknown. In our study, two Brassica napus genotypes with differential NUEs, xiangyou 15 and 814, and Atclca-2 mutant and AtCAX4 over-expression line (AtCAX4-OE) of Arabidopsis thaliana, were used to investigate Cd2+ stress responses. We found that the Brassica napus genotype, with higher NUE, was more sensitive to Cd2+ stress. The AtCAX4-OE mutant, with higher Cd2+ vacuolar sequestration capacity (VSC), limited NO3- sequestration into root vacuoles and promoted NUE. Atclca-2 mutants, with decreased NO3- VSC, enhanced Cd2+ sequestration into root vacuoles and conferred greater Cd2+ tolerance than the WT. This may be due to the competition between Cd2+ andNO3- in the vacuoles for the energy provided by V-ATPase and V-PPase. Regulating the balance between Cd2+ and NO3- vacuolar accumulation by inhibiting the activity of CLCa transporter and increasing the activity of CAX4 transporter will simultaneously enhance both the NUE and Cd2+ tolerance of Brassica napus, essential for improving its Cd2+ phytoremediation potential.


Assuntos
Arabidopsis/metabolismo , Brassica napus/metabolismo , Cádmio/toxicidade , Nitrogênio/metabolismo , Arabidopsis/efeitos dos fármacos , Brassica napus/efeitos dos fármacos , Cádmio/metabolismo , Clorofila/metabolismo , Glutamato-Amônia Ligase/metabolismo , Malondialdeído/metabolismo , Nitrato Redutase/metabolismo , Prolina/metabolismo , Bombas de Próton/metabolismo , Vacúolos/metabolismo
7.
BMC Plant Biol ; 19(1): 190, 2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31068146

RESUMO

BACKGROUND: The functional characteristics of SLAC/SLAH family members isolated from Arabidopsis thaliana, poplar, barley and rice have been comprehensively investigated. However, there are no reports regarding SLAC/SLAH family genes from Rosaceae plants. RESULTS: In this study, the function of PbrSLAH3, which is predominately expressed in pear (Pyrus bretschneideri) root, was investigated. PbrSLAH3 can rescue the ammonium toxicity phenomenon of slah3 mutant plants under high-ammonium/low-nitrate conditions. In addition, yeast two-hybrid and bimolecular fluorescence complementation assays confirmed that PbrSLAH3 interacts with PbrCPK32. Moreover, when PbrSLAH3 was co-expressed with either the Arabidopsis calcium-dependent protein kinase (CPK) 21 or PbrCPK32 in Xenopus oocytes, yellow fluorescence was emitted from the oocytes and typical anion currents were recorded in the presence of extracellular NO3-. However, when PbrSLAH3 alone was injected, no yellow fluorescence or anion currents were recorded, suggesting that anion channel PbrSLAH3 activity was controlled through phosphorylation. Finally, electrophysiological and transgene results showed that PbrSLAH3 was more permeable to NO3- than Cl-. CONCLUSION: We suggest that PbrSLAH3 crossing-talk with PbrCPK32 probably participate in transporting of nitrate nutrition in pear root.


Assuntos
Canais Iônicos/metabolismo , Nitratos/metabolismo , Proteínas de Plantas/metabolismo , Proteínas Quinases/metabolismo , Pyrus/enzimologia , Compostos de Amônio/toxicidade , Animais , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Fenômenos Eletrofisiológicos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Mutação/genética , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Filogenia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Pyrus/efeitos dos fármacos , Pyrus/genética , Xenopus
8.
Plant Physiol Biochem ; 140: 9-17, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31078053

RESUMO

The mutants Atnoa1 and Atnia1nia2noa1-2 having a defective chloroplast developmental process, showed enhanced chlorophyll levels when they were grown on Murashige and Skoog (MS) medium and on exposure with uranium (U) on Hoagland medium. Thus we hypothesized that these mutants probably produced NO in MS medium and on exposure with U. Wild-type Col-0, Atnoa1, Atnia1nia2noa1-2 plants were cultured on modified Hoagland and 1/10 MS media and NO generation in the roots of these mutants was monitored using NO selective fluorescent dyes, DAF-2DA and Fl2E. Both Atnoa1 and Atnia1nia2noa1-2 triple mutants produced NO as observed by increases in DAF-2T and Fl2E fluorescence when these mutants were grown on MS medium but not on Hoagland medium. In presence of NO scavenger, methylene blue (MB, 200 µM), DAF-2T and Fl2E fluorescence was completely abolished. On the other hand treatment of the plants with 25 µM U triggered NO generation. U-treated Atnoa1 and Atnia1nia2noa1-2 plants upregulated genes (POR B, POR D, CHL D) involved in the chlorophyll biosynthesis. From these results it was concluded that Atnoa1 and Atnia1nia2noa1-2 are conditional NO producers and it appears that NO generation in plants substantially depends on growth medium and NIA1, NIA2 or NOA1 does not appear to be really involved in NO generation in MS medium or after U exposure.


Assuntos
Arabidopsis/metabolismo , Óxido Nítrico/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Mutação/genética , Urânio/farmacologia
9.
Plant Physiol Biochem ; 140: 113-121, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31100704

RESUMO

Soil salinity is a major abiotic stress affecting plant growth and yield, due to both osmotic and ionic stresses. JUBGBRUNNEN1 (JUB1) is a NAC family transcription factor that has been shown to be involved in responses to abiotic stresses, such as water deficit, osmotic, salinity, heat and oxidative stress. In Arabidopsis thaliana (Arabidopsis), JUB1 has been shown to improve plant stress tolerance by regulating H2O2 levels. In the horticultural crop, Solanum lycopersicum cv. Moneymaker (tomato), overexpression of AtJUB1 has been shown to partially alleviate water deficit stress at the vegetative stage. In this study, we investigated the effect of Arabidopsis JUB1 overexpression in salinity tolerance in tomato. In hydroponically grown tomato seedlings, AtJUB1 overexpression results in higher prolines levels and improves the maintenance of water content in the plant under salinity stress. The transgenic tomato plants are more tolerant to salinity stress compared to control lines based on plant biomass. However, at the reproductive stage, we found that overexpression of AtJUB1 only provided marginal improvements in yield-related parameters, in the conditions used for the current work. The combination of improved water deficit and salinity stress tolerance conferred by AtJUB1 overexpression may be beneficial when tomato plants are grown in the field under marginal environments.


Assuntos
Arabidopsis/metabolismo , Lycopersicon esculentum/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lycopersicon esculentum/efeitos dos fármacos , Proteínas de Plantas/genética , Prolina/metabolismo , Tolerância ao Sal , Cloreto de Sódio/farmacologia , Fatores de Transcrição/genética
10.
Int J Mol Sci ; 20(9)2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31067662

RESUMO

Potassium (K+) and phosphorous (Pi) are two of the most important nutrients required by plants and there is an interest in studying how they are acquired. Most studies have focused on the characterization of the mechanisms involved in K+ and Pi uptake and their distribution within the plants, as well as the regulatory mechanisms involved. Evidence is emerging which points to interactions in the nutrition of different nutrients and to the existence of crosstalk in the signaling cascades regulating their acquisition. However, the interaction between K+ and Pi has been scarcely studied. Here we show that high concentrations of K+ in the external solution inhibit Pi uptake and impair Pi nutrition in Arabidopsis plants, resulting in the induction of phosphate starvation response (PSR) and the upregulation of genes encoding root phosphate uptake systems. The high K+-induced PSR depends on the PHR1 and PHL1 transcription factors that are key pieces of Pi signaling in Arabidopsis. Importantly, high K+ reduces arsenic accumulation in plants and its toxic effects. The results presented may help to design strategies to reduce Pi deficiency as well as the accumulation of arsenic in crops.


Assuntos
Arabidopsis/metabolismo , Arsênico/toxicidade , Fosfatos/metabolismo , Potássio/metabolismo , Estresse Fisiológico , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Transporte de Íons , Fosfatos/deficiência , Potássio/farmacologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
11.
J Agric Food Chem ; 67(21): 5997-6006, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31056906

RESUMO

A fluoride export gene ( CsFEX) was newly found and isolated from Camellia sinensis, and its functions in detoxifying F were investigated in transgenic Escherichia coli and Arabidopsis thaliana. CsFEX contains two crcB domains, which is the typical structure in plants. The expression of CsFEX in C. sinensis is tissue-specific and related to maturity of leaves, and its expression is significantly induced by F treatments in different tissues of C. sinensis, particularly in leaves. Additionally, the growth of C. sinensis, E. coli, and A. thaliana can all be inhibited by F treatment. However, the growth of CsFEX-overexpression E. coli was increased with lower F content under F treatment compared to the control. Similarly, the germination and growth of CsFEX-overexpression A. thaliana were enhanced with lower F content under F treatment compared to the wild type. CsFEX relieves F toxicity in the transgenic E. coli and A. thaliana by alleviating F accumulation.


Assuntos
Arabidopsis/metabolismo , Camellia sinensis/genética , Escherichia coli/metabolismo , Fluoretos/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Transporte Biológico , Camellia sinensis/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Fluoretos/toxicidade , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética
12.
J Plant Physiol ; 238: 1-11, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31121522

RESUMO

Treatment of Arabidopsis thaliana seedlings with the PSII-inhibiting herbicide atrazine results in xenobiotic and oxidative stress, developmental arrest, induction of senescence and cell death processes. In contrast, exogenous sucrose supply confers a high level of atrazine stress tolerance, in relation with genome-wide modifications of transcript levels and regulation of genes involved in detoxification, defense and repair. However, the regulation mechanisms related to exogenous sucrose, involved in this sucrose-induced tolerance, are largely unknown. Characterization of these mechanisms was carried out through a combination of transcriptomic, metabolic, functional and mutant analysis under different conditions of atrazine exposure. Exogenous sucrose was found to differentially regulate genes involved in polyamine synthesis. ARGININE DECARBOXYLASE ADC1 and ADC2 paralogues, which encode the rate-limiting enzyme (EC 4.1.1.19) of the first step of polyamine biosynthesis, were strongly upregulated by sucrose treatment in the presence of atrazine. Such regulation occurred concomitantly with significant changes of major polyamines (putrescine, spermidine, spermine). Physiological characterization of a mutant affected in ADC activity and exogenous treatments with sucrose, putrescine, spermidine and spermine further showed that modification of polyamine synthesis and of polyamine levels could play adaptive roles in response to atrazine stress, and that putrescine and spermine had antagonistic effects, especially in the presence of sucrose. This interplay between sucrose, putrescine and spermine is discussed in relation with survival and anti-death mechanisms in the context of chemical stress exposure.


Assuntos
Arabidopsis/efeitos dos fármacos , Atrazina/farmacologia , Herbicidas/farmacologia , Putrescina/metabolismo , Espermidina/metabolismo , Espermina/metabolismo , Sacarose/farmacologia , Arabidopsis/metabolismo , Morte Celular/efeitos dos fármacos , Resistência a Herbicidas , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/efeitos dos fármacos , Reação em Cadeia da Polimerase em Tempo Real , Plântula/efeitos dos fármacos , Plântula/metabolismo , Transcriptoma/efeitos dos fármacos
13.
J Plant Physiol ; 238: 12-19, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31121523

RESUMO

In this study, the effect of 24-Epibrassinolide (EBL) on antioxidant system in Arabidopsis thaliana were investigated under arsenate [As(V)] stress. The enzyme activity of superoxide dismutase (SOD) and catalase (CAT), total antioxidant status, malondialdehyde (MDA) level and free proline content, as well as the expression levels of SOD isoforms (Cu-ZnSODs, FeSODs and MnSOD), CAT isoforms (CAT1, CAT2 and CAT3), some heat shock proteins (Hsp70-4 and Hsp90-1) and proline biosynthesis (P5CS1 and P5CS2) genes were determined in rosette leaves of eight-week old plants under exposure of 100 and 200 µM As(V) and/or 1 µM EBL treatments for 24 h. Total SOD and CAT enzyme activities increased as a result of 100 µM As(V) + EBL treatments compared to 100 µM As(V) treatment. Total antioxidant and proline levels increased in plants subjected to As(V), and the treatment of EBL together with stress caused further increase. As the MDA level increased in As-treated plants, 100 µM As(V) + EBL treatment decreased MDA level. Transcript levels of CSD1, CSD2, FSD1, FSD2, MSD1 and CAT2 genes increased as a result of combined treatment of EBL and As(V) compared to control and alone stress treatments (except CSD1 gene). Expression level of CSD3, CAT1 and CAT3 genes were downregulated in response to As(V) and/or EBL treatments. EBL application alone and in combination with As(V) elevated the expression level of P5CS1 gene dramatically. Treatment with 100 µM As(V) and EBL increased the transcript level of Hsp70-4 and Hsp90-1 genes in leaves compared to 100 µM As(V) treatment. To our best knowledge, this is the first detailed study to evaluate the improving effect of EBL on antioxidant defense system at biochemical and transcriptional level in A. thaliana plants under As(V) stress.


Assuntos
Arabidopsis/metabolismo , Arsênico/toxicidade , Brassinosteroides/farmacologia , Esteroides Heterocíclicos/farmacologia , Arabidopsis/efeitos dos fármacos , Catalase/metabolismo , Relação Dose-Resposta a Droga , Proteínas de Choque Térmico/metabolismo , Malondialdeído/metabolismo , Prolina/metabolismo , Isoformas de Proteínas , Estresse Fisiológico/efeitos dos fármacos , Superóxido Dismutase/metabolismo
14.
Plant Physiol Biochem ; 141: 51-59, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31128563

RESUMO

Brassinosteroids (BRs) play a crucial role in improving plant resistance to various environmental stresses. In this study, we aimed to explore the potential role of BRs in protecting plants from antimony (Sb) toxicity. In the in vitro agar-plate culture experiments, the level changes of BR in wide-type plants and BR biosynthesis mutant dwrf4-1 significantly affected the corresponding response of Arabidopsis to Sb stress. Increasing the BR content significantly enhanced Sb-induced root growth inhibition and lowering the BR level appeared to reduce the plant sensitivity to Sb stress. Foliar application of eBL, however, significantly decreased the Sb accumulation and peroxidation of membrane lipids, increased the contents of chlorophyll and proline, and further boosted and strengthened the antioxidant enzymes activities. These experiments demonstrated that BRs played an important role in regulating heavy metal stress responses in plants and exogenous foliar spray of eBL was an important method for alleviating toxicity of Sb.


Assuntos
Antimônio/química , Arabidopsis/efeitos dos fármacos , Arabidopsis/fisiologia , Brassinosteroides/química , Estresse Fisiológico/efeitos dos fármacos , Antioxidantes/química , Proteínas de Arabidopsis/genética , Biodegradação Ambiental , Brassinosteroides/farmacologia , Clorofila/química , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/química , Hidroponia , Peroxidação de Lipídeos , Malondialdeído/metabolismo , Metais Pesados/química , Estresse Oxidativo , Reguladores de Crescimento de Planta/química , Reguladores de Crescimento de Planta/farmacologia , Prolina/química
15.
J Agric Food Chem ; 67(22): 6143-6149, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31083983

RESUMO

Strigolactones (SLs) are one of the plant hormones that control several important agronomic traits, such as shoot branching, leaf senescence, and stress tolerance. Manipulation of the SL biosynthesis can increase the crop yield. We previously reported that a triazole derivative, TIS108, inhibits SL biosynthesis. In this study, we synthesized a number of novel TIS108 derivatives. Structure-activity relationship studies revealed that 4-(2-phenoxyethoxy)-1-phenyl-2-(1 H-1,2,4-triazol-1-yl)butan-1-one (KK5) inhibits the level of 4-deoxyorobanchol in roots more strongly than TIS108. We further found that KK5-treated Arabidopsis showed increased branching phenotype with the upregulated gene expression of AtMAX3 and AtMAX4. These results indicate that KK5 is a specific SL biosynthesis inhibitor in rice and Arabidopsis.


Assuntos
Reguladores de Crescimento de Planta/antagonistas & inibidores , Terpenos/antagonistas & inibidores , Triazóis/química , Triazóis/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Oryza/efeitos dos fármacos , Oryza/genética , Oryza/metabolismo , Reguladores de Crescimento de Planta/biossíntese , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Terpenos/metabolismo , Triazóis/síntese química
16.
BMC Plant Biol ; 19(1): 152, 2019 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-31010418

RESUMO

BACKGROUND: During sexual reproduction, pollen grains land on the stigma, rehydrate and produce pollen tubes that grow through the female transmitting-tract tissue allowing the delivery of the two sperm cells to the ovule and the production of healthy seeds. Because pollen tubes are single cells that expand by tip-polarized growth, they represent a good model to study the growth dynamics, cell wall deposition and intracellular machineries. Aiming to understand this complex machinery, we used a low throughput chemical screen approach in order to isolate new tip-growth disruptors. The effect of a chemical inhibitor of monogalactosyldiacylglycerol synthases, galvestine-1, was also investigated. The present work further characterizes their effects on the tip-growth and intracellular dynamics of pollen tubes. RESULTS: Two small compounds among 258 were isolated based on their abilities to perturb pollen tube growth. They were found to disrupt in vitro pollen tube growth of tobacco, tomato and Arabidopsis thaliana. We show that these 3 compounds induced abnormal phenotypes (bulging and/or enlarged pollen tubes) and reduced pollen tube length in a dose dependent manner. Pollen germination was significantly reduced after treatment with the two compounds isolated from the screen. They also affected cell wall material deposition in pollen tubes. The compounds decreased anion superoxide accumulation, disorganized actin filaments and RIC4 dynamics suggesting that they may affect vesicular trafficking at the pollen tube tip. CONCLUSION: These molecules may alter directly or indirectly ROP1 activity, a key regulator of pollen tube growth and vesicular trafficking and therefore represent good tools to further study cellular dynamics during polarized-cell growth.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Tubo Polínico/crescimento & desenvolvimento , Bibliotecas de Moléculas Pequenas/farmacologia , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Arabidopsis/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Germinação/efeitos dos fármacos , Conformação Molecular , Tubo Polínico/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/química , Superóxidos/metabolismo
17.
Plant Physiol Biochem ; 139: 738-745, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31010613

RESUMO

Weisiensin B, a new ent-kaurene diterpenoid isolated from Isodon weisiensis (C. Y. Wu) H. Hara, exhibited phytotoxic effects on root growth and lateral root development in Arabidopsis thaliana seedlings. Primary root growth and lateral root formation in A. thaliana seedlings were significantly inhibited by 10-20 µM weisiensin B. Additionally, the role of weisiensin B in response to polar auxin transport in A. thaliana roots was investigated using a PIN promoter (PIN::GUS), a green fluorescent protein (GFP) fusion protein reporter (PINs::PINs:GFP), and DR5::GUS and DR5::GFP reporter genes. The results indicated that weisiensin B reduced the expression of PIN2, PIN3, PIN4, PIN7, and AUX1 genes and significantly decreased the abundance of PIN2-GFP, PIN3-GFP, PIN4-GFP, PIN7-GFP, and AUX1-GFP fusion proteins at their respective cellular locations, simultaneously causing auxin accumulation in the root apex. These results suggest that weisiensin B interferes with polar auxin transport in A. thaliana roots, resulting in auxin accumulation in the root meristematic cells and the inhibition of root growth and lateral root development.


Assuntos
Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Transporte Biológico/efeitos dos fármacos , Diterpenos/farmacologia , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos
18.
Plant Physiol Biochem ; 139: 540-547, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31029027

RESUMO

Following a stress event, jasmonate-dependent signaling pathway triggers a shift from growth to defense responses that are accompanied by the cessation of growth in many plants. However, the processes leading to this growth inhibition remain obscure. In this study, we provide evidence for a rapid inhibition of cell hydraulic conductivity (Lp) by methyl jasmonate (MeJA) in the roots of wild-type Arabidopsis within 0.5 h of 20 and 50 µM MeJA treatments. We also demonstrate that MeJA did not affect Lp in fad3-2 and fad7-2 Arabidopsis mutants that are deficient in jasmonate precursor, linolenic acid. The reductions of Lp in wild-type plants were accompanied by the down-regulation of several plasma membrane intrinsic protein (PIP) isoforms, and dephosphorylation. Treatments with HgCl2 did not further reduce Lp in the wild-type plants, but significantly reduced Lp in the fad3-2 and fad7-2 that had been first treated with MeJA. Continuous prolonged exposure to exogenous 50 µM MeJA inhibited the relative growth rates (RGR) of shoots and net photosynthesis (Pn) in the Arabidopsis wild-type and fad7-2 plants, but had no effect on the RGR of roots. The results demonstrated that a reduction of aquaporin (AQP)-mediated water transport was the initial target of MeJA exposure, and may contribute to the processes of growth inhibition by MeJA.


Assuntos
Acetatos/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Ciclopentanos/farmacologia , Oxilipinas/farmacologia , Água/metabolismo , Transporte Biológico/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácido Okadáico/farmacologia
19.
Mol Biotechnol ; 61(6): 442-450, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30980224

RESUMO

Soil salinity imposes a serious threat to the productivity of agricultural crops. Among several other transporters, high-affinity K+ transporter (HKT)'s play an important role in reducing the phytotoxicity of Na+. Expression of Eutrema salsugineum (a halophyte) HKT1;2 is induced upon salt exposure. To elucidate the role of its promoter, we compared the sequences of HKT1;2 promoters from E. salsugineum (1822 bp) and E. botschantzevii (1811 bp) with Arabidopsis thaliana HKT1;1 (846 bp) promoter. In silico analysis predicted several cis-acting regulatory elements (GT-1 elements, core motifs of DRE/CRT, MYC/MYB-recognition sites and ACGT elements). Activities of the three promoters were analyzed by measuring HKT1;1 and/or HKT1;2 transcript level in the Athkt1;1 mutant plants. NaCl tolerance of the transgenics was also assessed. Our results depicted that expressing either AtHKT1;1 or EsHKT1;2 coding regions under the control of AtHKT1;1 promoter, almost reversed the hypersensitivity of the mutant for salt, on contrarily, when AtHKT1;1 coding sequence expressed under either Es or EbHKT1;2 promoters did not. Changes in shoot Na+/K+ concentrations under salt exposure is significantly consistent with the complementation ability of the mutant. The transcript concentration for genes under the control of either of Eutrema promoters, at control level was very less. This may suggest that either an important upstream response motif is missed or that A. thaliana misses a transcriptional regulator that is essential for salt-inducible HKT1 expression in Eutrema.


Assuntos
Arabidopsis/genética , Brassicaceae/genética , Proteínas de Transporte de Cátions/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Tolerância ao Sal/genética , Simportadores/genética , Arabidopsis/efeitos dos fármacos , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Sequência de Bases , Brassicaceae/efeitos dos fármacos , Brassicaceae/crescimento & desenvolvimento , Brassicaceae/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Teste de Complementação Genética , Transporte de Íons/efeitos dos fármacos , Mutação , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plantas Geneticamente Modificadas , Potássio/metabolismo , Regiões Promotoras Genéticas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Sódio/metabolismo , Cloreto de Sódio/farmacologia , Especificidade da Espécie , Estresse Fisiológico/genética , Simportadores/metabolismo
20.
Molecules ; 24(7)2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-30959741

RESUMO

The present results dealing with the antiphytoviral activity of essential oil indicate that these plant metabolites can trigger a response to viral infection. The essential oil from Micromeria croatica and the main oil components ß-caryophyllene and caryophyllene oxide were tested for antiphytoviral activity on plants infected with satellite RNA associated cucumber mosaic virus. Simultaneous inoculation of virus with essential oil or with the dominant components of oil, and the treatment of plants prior to virus inoculation, resulted in a reduction of virus infection in the local and systemic host plants. Treatment with essential oil changed the level of alternative oxidase gene expression in infected Arabidopsis plants indicating a connection between the essential oil treatment, aox gene expression and the development of viral infection.


Assuntos
Satélite do Vírus do Mosaico do Pepino/antagonistas & inibidores , Cucumovirus/efeitos dos fármacos , Óleos Voláteis/farmacologia , Doenças das Plantas/prevenção & controle , Arabidopsis/efeitos dos fármacos , Arabidopsis/virologia , Cucumovirus/patogenicidade , Regulação Viral da Expressão Gênica/efeitos dos fármacos , Lamiaceae/química , Oxirredutases/antagonistas & inibidores , Doenças das Plantas/virologia
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